One of two proposed locations for a second commercial runway at Palm Beach International Airport would be nearly obsolete just four years after it is scheduled to open, according to an initial review of the project.

Federal aviation officials said Tuesday that their proposal to build the runway 800 feet north of the existing commercial runway would not create nearly as much space for additional planes as a similar plan proposed by airport officials. That plan would lengthen the southernmost general aviation runway 4,800 feet so it can accommodate commercial jets.

Under the Federal Aviation Administration's proposal, the airport would be able to accommodate 260,000 flights a year. By 2018, the airport would be almost at full capacity.

The airport's plan can accommodate 385,203 flights a year, giving officials much more breathing room before they would have to consider future expansions.

The difference: the FAA's proposal would eliminate the airport's crosswind runway - which runs northwest to southeast - reducing the number of planes that can take off and land. The airport's plan just shortens it, so that it no longer intersects with the main runway.

Federal aviation officials are considering both plans as part of a three-year environmental study of the runway project. They held a workshop Tuesday night with residents living around the airport to discuss the locations.

Although the FAA's plan can't accommodate as many planes, federal officials say they are required to evaluate both options to determine the environmental impacts the locations would have on surrounding homes, schools and historic sites.

They have not endorsed either option, but are expected to choose one before completing a draft of the environmental study next year.

"You can't have tunnel vision and say, 'this one gives me the most capacity,'" said Jackie Sweatt-Essick, a regional environmental program manager for the FAA. "You still have to weigh the impacts."

Many residents at Tuesday's workshop argued the runway isn't needed. They say private, general aviation planes should be relocated to other county airports in Lantana and Palm Beach Gardens to free up room for commercial jets.

Private planes make up about 65 percent of the traffic at PBIA. But unlike commercial airliners, they aren't required to pay a fee to land there. Residents argue the fee could help divert private planes to other airports.

"What they need to do first before they do any other airport improvement is move general aviation," said Jim Young, a West Palm Beach resident.

West Palm Beach officials also want to see private planes relocated and charged to land at the airport.

"We just want the FAA to give as much credence to the quality of life of our residents as they do a five-minute delay," said West Palm Beach Commissioner Bill Moss. "We feel strongly that they have a responsibility to consider all of the alternatives. The one we think is probably the most reasonable is to charge those that want to land general aviation at PBIA."

As part of its study, the FAA considered redirecting traffic to other county airports. The concept was tossed out because officials said it wouldn't work.

Airports Director Bruce Pelly said the newest master plan for the north county airport in Palm Beach Gardens would extend the airport's runway to allow different categories of jets to land there. However, Palm Beach Gardens city officials must sign off on the extension before it moves forward.

The master plan, which county commissioners will discuss early next year, also includes space for a U.S. Customs office at the north county airport, Pelly said. The office could help divert some international flights from PBIA.

Airport officials have maintained that the runway is needed to reduce delays, which are expected to average about 20 minutes by 2018. Both plans being considered by the FAA would reduce those delays to about 2 minutes.

Neither location will leave enough distance between the two runways to allow simultaneous takeoffs and landings. But a second runway would allow planes to take off and land more quickly.

Residents have until Dec. 27 to submit comments to the FAA. They can be mailed to Lindy McDowell, Federal Aviation Administration, Orlando Airports District Office, 5950 Hazeltine National Drive, Suite 400, Orlando, Fla. 32822.